abstract class A {
  void a();
}

class A1 implements A {
  void a() {
    print("a1");
  }
}

class A2 implements A {
  void a() {
    print("A2");
  }
}

class B {
  int t;
  String aa;

  void c() {
    print("c");
  }
}

class A1B = B with A1;

class A2B = B with A2;

class A3B extends B with A2 {}
